#pragma once

#include "fgc/ImageQuality.h"

#include <string>

namespace fgc {

// The exposure/gain control law: given what an image turned out like, decide
// whether to keep it and what to change if not. Pure (no camera, no I/O, no
// clock) so the whole correction strategy is unit-testable.

struct CaptureSettings {
    double exposure_us = 0.0;
    double gain_db     = 0.0;
};

struct PolicyParams {
    double target_mean       = 110.0;   // desired mean luma, 0..255
    double mean_tolerance    = 12.0;    // accept within +-this of the target
    double clip_max_fraction = 0.005;   // 0.5% blown pixels is the ceiling
    double exposure_min_us   = 50.0;
    double exposure_max_us   = 20000.0; // doubles as the motion-blur budget
    double gain_max_db       = 12.0;
    double damping           = 0.8;     // <1 damps the correction, preventing oscillation
    // Blur is judged RELATIVE to the same angle's own history: a foggy horizon is
    // legitimately low-detail, so an absolute threshold would retry forever on it.
    double blur_relative_floor = 0.5;   // retry below this fraction of the reference
    double blur_absolute_floor = 0.0;   // 0 disables the catastrophic-blur backstop
};

struct Verdict {
    bool            accept = false;
    std::string     reason;   // "ok" / "clipped" / "dark" / "bright" / "blur" / "saturated"
    CaptureSettings next;     // settings to use for the next attempt (== current if accepting)
};

// Judge one attempt. `reference_sharpness` is this angle's recent sharpness; pass
// 0 when unknown, which skips the relative blur check.
//
// Precedence matters: clipping outranks the mean, because a bright sky can blow
// out while the average still looks perfectly reasonable - and blown highlights
// are unrecoverable, whereas a slightly dark frame is not.
Verdict evaluate(const ImageMetrics& m, const CaptureSettings& current, const PolicyParams& p,
                 double reference_sharpness = 0.0);

// Rank attempts so "best so far" is well defined: sharpness discounted by how far
// the exposure strayed. Higher is better.
double score(const ImageMetrics& m, const PolicyParams& p);

}  // namespace fgc